1. Field of the Invention
The present invention relates to a glossiness determining device, a color measuring device, an image forming apparatus, and a glossiness determination method.
2. Description of the Related Art
In image forming apparatuses, such as printers, a process called color management is performed to suppress variations in outputs due to device-specific characteristics and enhance the reproducibility of outputs with respect to inputs. The color management is to perform color conversion between a standard color space and device dependent colors based on a device profile (ICC profile) in which device-specific characteristics are written, and enhance the reproducibility of output images. When the device profile is generated or corrected, an image forming apparatus actually forms a test pattern, in which a number of reference color charts (patches) are arrayed, on a sheet and performs color measurement on each of the patches contained in the test pattern.
As a color measuring device that performs the color measurement on the patches, a spectrophotometric color measuring device is widely used. The spectrophotometric color measuring device can obtain spectral reflectivity for each wavelength, and therefor can perform the color measurement with high accuracy. However, the spectrophotometric color measuring device is expensive, and thus there is a need to perform the color measurement with high accuracy by using a less expensive device.
As an example of a method of realizing the color measurement with high accuracy at low cost, there is a method of capturing an image of the patches by an image capturing device, and converting RGB values of the patches obtained by the image capturing to color specification values in the standard color space. For example, Japanese Laid-open Patent Publication No. 2012-63270 describes a color measuring device that, by using a two-dimensional sensor, simultaneously captures an image of color measurement target patches formed on a sheet and a reference chart containing multiple reference patches having color specification values specified in advance, and calculates color measurement values of the color measurement target patches based on RGB values of the color measurement target patches and RGB values of the reference patches that are contained in captured images.
However, in the color measuring device described in Japanese Laid-open Patent Publication No. 2012-63270, it is impossible to obtain the glossiness of a subject having its image captured by the two-dimensional sensor.
In view of the above, there is a need to provide a glossiness determining device, a color measuring device, an image forming apparatus, and a glossiness determination method capable of obtaining the glossiness of a subject having its image captured by a two-dimensional sensor.